I hate it when I can't think clearly. I cleaned the section of the layout where the sound was cutting out but did not believe that was the issue. I still had good control and response from the engines there. I took my own advice from another post about this issue.
I ran the consist again today. This time as I was running it, I accelerated to 45 MPH after stretching the train out at about 10MPH. As soon as the engines reached full speed, the sound cut out. So I knew what it was now. It wasn't that spot on the layout. This was an old consist (lash-up) already in the remote. As soon as I turned the clickity clack off, all sounds worked just as they should.
I want to guess that the clickity clack is coming on by default again? or maybe it's from an older version of DCS biting me here?